Chris,
You can stuff more wheel under the front with 15" and even more with 16" or
17" wheels, because you can increase the negative offset. I am calibrated in
rear spacing, not offset, but for 15" wheels, I know the rear spacing you
should aim for is between 4&3/4 and 4&7/8 inches. Let's split the
difference, which is 4.812". I have a set of 7" and a set of 7.5" wheels for
the front. I measured the lip-to-lip width of a wheel and it's 8.250", so
the center of the wheel is at 4.125". The thickness of the mounting flange
in my case is 5/8", so half that is where the rear flange surface is, or
4.125 - 0.312 = 3.813"; i.e., the rear spacing for zero offset. Compare this
to the target rear spacing of 4.812" and you see the offset, at least for my
wheels, it is almost exactly -1" or -25.4 mm. The same wheels fit perfectly
on the rear, but I've flared the rear fender lips and use 8.5" wide wheels
with the same rear spacing/offset. If I run through the same calculation for
a 7" wide wheel, assuming all else is the same, I get an offset of -1.25"
or -32mm. This is 10mm more offset than the Panasport wheels Mike Sutter
uses. Got an extra 3/8" in reserve Mike?
If you use big wheels up front, you definitely need to do some serious
trimming of the lower valance. If done well, it won't be noticeable. I would
highly recommend that you do it now, just in case you ever decide to go to a
larger size somewhere down the road. (Sorry Norm. :()
Bob Palmer
rpalmer@ucsd.edu
rpalmer@brobeck.com
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